EVALUATION OF THE EFFECTS OF ALTERNATE, CONVENTIONAL AND FIXED FURROW IRRIGATION UNDER WATER APPLICATION LEVELS ON WATER SAVING AND WATER PRODUCTIVITY OF CABBAGE (BRASSICA OLERACEA CAPITATA L.) AT TONY FARM, DIRE DAWA

Abstract

This study attempted to evaluate the effects of Alternate, Conventional and Fixed Furrow Irrigation under Different Water Application Levels on Water saving and water productivity of Cabbage (Brassica oleraceacapitata L.).The objective of this study was to evaluate and compare water saving potential, water productivity and identify the most appropriate methods of furrow based water application methods,alternate(AFI), conventional (CFI) and fixed (FFI) furrow irrigation using different water application levels. Field experiment was designed as a two factor factorial experiment in RCBD, replicated three times. The two factors were irrigation systems and water application levels. The results revealed that the total head yield (THY) and fresh head weight per plant (FHW) were highly significantly (P<0.01) affected by both irrigation method and application levels. Maximum mean as 34.38 t ha-1of THW and 3.86 kg per plant FHW respectively observed under CFI, while maximum FHW of 3.86 kg per plant and 34.44 t ha-1THY was recorded under100% ETc, water ALs respectively. Unmarketable head yield (UMHY) was significantly (P<0.05) affected by ALs.The average yield of 0.29t ha-1, 0.43 t ha-1 and 0.60 t ha-1 were recorded under 100%, 80% and 60% water application level. Marketable head yield (MHY) was highly significantly (P<0.01) affected by both irrigation methods and application levels.The largest MHY mean value of IMs was 34.08 t ha-1 produced under CFI and 34.21t ha-1 perceived under (100% ETc)ALs. Maximum water saved resulted from AFI and FFI, with 60%, 80% and 100% of ETc application depth was equally computed as 70%, 60% and 50% which could irrigate additional area of 2.33, 1.5 and 1ha for each treatment respectively contrarily yield reduction was higher in FFI followed by AFI and CFI with the same ALs. Irrigation water use efficiency (IWUE), crop water use efficiency (CWUE) and economic water productivity (EWP) were highly significantly (P<0.01) affected by both IMs and ALs and were significant at (P<0.05) affected by interaction of IMs and ALs. The highest and the lowest mean crop (CWUE and IWUE), and (EWP) were recorded by AFI and CFI irrigation. Whereas ,under ALs the highest and the lowest mean CWUE, IWUE and EWP were recorded by 60% and 100% ETc application depth. This indicates CWUE, IWUE and EWP significantly increased with irrigation depth decreased or deficit level increase. NR (net return) produced per hectare was higher in AFI followed by CFI and FFI. In case of BCR, AFI with 80% and 60% ETc was higher than FFI and the smallest by CFI of 60% and 80% ETc deficit level. Generally from over all investigation of CWUE, IWUE, EWP, NR and BCR alternative furrow irrigation (AFI) was better than FFI and CFI for the water scarce area. So Alternative furrow irrigation system is relatively the best technology among the tested technologies to be recommended for the communities of the study area